The company had announced a closed beta test for the Pie update program for the devices, about 2 months ago. And after ironing out the kinks that users reported during the beta, the update has finally been released for all users.
In case you have forgotten, OnePlus had promised to deliver the Android Pie Update for OnePlus 3 and OnePlus 3T about ten months ago. It took an awfully long wait to get here, but it's better late than never I suppose.
What's new in the Android Pie Update for OnePlus 3 and OnePlus 3T?
Apart from the obvious OS upgrade from Android 8.1 Oreo to Android 9.0 Pie, there are a few additional features which the company has baked in to the firmware.
The OxygenOS 9.0.2 brings a new user interface, and the firmware has been updated with the April 2019 Android Security Patch. There is a new Do Not Disturb mode, which allows you to customize the time range.
According to some users, the Android Pie Update for OnePlus 3 and OnePlus 3T weighs about 1.6GB (from Android 8.1 Stable) and you can download it from the link posted on the official forums. The name of the update zip file is OnePlus3Oxygen_16_OTA_082_all_1905110006_fdc22.zip.
The firmware version is ONEPLUS A3003_28_190511.
The Android Pie Update for OnePlus 3 and OnePlus 3T is being rolled out in batches, and might take a few days to reach you. If you can't wait for it, you can try using the Oxygen Updater app from the Google Play Store to get the update immediately.